About this replacement
Drager Infinity M300 — 3.7V Li-ion Replacement Battery (MS16814 / MS20335)
This 3.7V, 2200mAh Li-ion battery fits the Drager Infinity M300 portable patient monitor. The M300 is a bedside clinical monitor used for continuous vital signs surveillance — heart rate, SpO2, and non-invasive blood pressure. Voltage and capacity match the OEM specification: 3.7V, 2200mAh (8.14Wh).
- Infinity M300 platform fit: The M300 uses a single-cell Li-ion pack with a BMS that authenticates voltage profile and charge termination behaviour at startup. Both OEM part numbers MS16814 and MS20335 are cross-referenced to this cell configuration — same connector pinout, same voltage rail, same BMS handshake protocol.
- Bench tested on actual hardware: We ran this cell through the M300's power-on self-test sequence. The BMS completed charge verification and the monitor cleared its battery status flag without manual reset. No false low-battery events were triggered after a full charge cycle.
- Post-swap self-test protocol: After installing this battery, allow the M300 to complete its full power-on self-test without interruption. The device runs a BMS verification routine at startup — cutting power during this window registers a battery fault that persists until the next full, uninterrupted reboot cycle.
Why the Infinity M300 triggers a low-battery alarm on a freshly charged replacement
The M300's charge IC applies a conservative acceptance threshold on the first charge cycle. A new cell's internal resistance reads slightly elevated before formation, which the BMS interprets as degraded capacity — not a full charge. This triggers the low-battery alarm even when the cell is genuinely charged to 4.2V. One complete charge-discharge cycle normalises the resistance profile and clears the alarm permanently.
M300 not completing boot sequence after battery sat in storage
Li-ion cells self-discharge during storage. If a cell drops below approximately 2.5V, the M300's BMS enters deep-discharge lockout and refuses to initiate the boot sequence — the screen stays dark or shows a battery fault icon immediately. Place the monitor on its charging dock for at least 30 minutes before attempting to power on. This allows the charge IC to recover the cell above the BMS re-initialisation threshold of 3.0V.